Objectives: The Paced Auditory Serial Addition Test (PASAT) is used to assess cognitive status in multiple sclerosis (MS). Although the mathematical demands of the PASAT seem minor (single-digit arithmetic), cognitive psychology research links greater mathematical ability (e.g., algebra, calculus) to more rapid retrieval of single-digit math facts (e.g., 5+6=11). The present study evaluated the hypotheses that (a) mathematical ability is related to PASAT performance and (b) both the relationship between intelligence and PASAT performance as well as the relationship between education and PASAT performance are both mediated by mathematical ability. Methods: Forty-five MS patients were assessed using the Wechsler Test of Adult Reading, PASAT and Calculation Subtest of the Woodcock-Johnson-III. Regression based path analysis and bootstrapping were used to compute 95% confidence intervals and test for mediation. Results: Mathematical ability (a) was related to PASAT (β=.61; p<.001) and (b) fully mediated the relationship between Intelligence and PASAT (β=.76; 95% confidence interval (CI95)=.28, 1.45; direct effect of Intelligence, β=.42; CI95=−.39, 1.23) as well as the relationship between Education and PASAT (β=2.43, CI95=.81, 5.16, direct effect of Education, β=.83, CI95=−1.95, 3.61). Discussion: Mathematical ability represents a source of error in the clinical interpretation of cognitive decline using the PASAT. Domain-specific cognitive reserve is discussed. (JINS, 2016, 22, 375–378)

Working memory and information processing speed were examined in children with myelomeningocele and shunted hydrocephalus using the Children's Paced Auditory Serial Addition Test (CHIPASAT). The CHIPASAT was administered to 31 children with myelomeningocele and shunted hydrocephalus and 27 healthy siblings, all between 8 and 15 years of age. They also completed other standardized measures of working memory and processing speed. Children with myelomeningocele made fewer correct responses than siblings, although the magnitude of group differences declined as the rate of stimulus presentation increased. Children with myelomeningocele also made fewer consecutive correct responses and were more likely to provide correct but nonconsecutive responses, suggesting that they responded in a way that circumvents the working memory demands of the task. Standardized measures of processing speed and working memory accounted for significant variance in CHIPASAT performance after controlling for age, group membership, math skill, and general intellectual functioning. The results indicate that children with myelomeningocele and shunted hydrocephalus display deficits in working memory and information processing speed, and suggest that the CHIPASAT may provide a valid measure of these skills. (JINS, 2006, 12, 305–313.)

The paced auditory serial addition task (PASAT), in which subjects hear a number-string and add the two most-recently heard numbers, is a neuropsychological test sensitive to cerebral dysfunction. We mapped the brain regions activated by the PASAT using positron emission tomography (PET) and 15O-water to measure cerebral blood flow. We parsed the PASAT by mapping sites activated by immediate repetition of numbers and by repetition of the prior number after the presentation of the next number in the series. The PASAT activated dispersed non-contiguous foci in the superior temporal gyri, bifrontal and biparietal sites, the anterior cingulate and bilateral cerebellar sites. These sites are consistent with the elements of the task that include auditory perception and processing, speech production, working memory, and attention. Sites mediating addition were not identified. The extent of the sites activated during the performance of the PASAT accounts for the sensitivity of this test and justifies its use in a variety of seemingly disparate conditions. (JINS, 2004, 10, 26–34.)